As per error details, while retrieve the data from database connection was missed out due to some reasons the most common reasons are 1) firewall setting from web server to database server2) connection string.3) enable appropriate protocalls.

Without checking your code we are unable to resolve your error, Please share your code with us. so that we can help you better in order to resolve your issueThanksKoolprasd2003Editor, DotNetSpider MVMMicrosoft MVP 2014 [ASP.NET/IIS]